With growing demand for consumer electronics products, there is an increasingly great demand for power metal-oxide-semiconductor field effect transistors (MOSFETs). Power MOSFETs include two main types, i.e., vertical double-diffused MOSFET (VDMOS) and lateral double-diffused MOSFET (LDMOS). Among the two types, the trench VDMOS transistor (or Trench Vertical MOS) has advantages such as high degree of device integration, low on-resistance, lower gate-drain charge density, and high current capacity. Thus, the trench VDMOS transistor has lower switching loss and fast switching speed, and is widely used in the field of power devices.
However, using current fabrication processes, the drive current of the existing VDMOS transistor is still relatively small. The disclosed methods and devices are directed to solve one or more problems set forth above and other problems.